5c: do not use R9 and R10

This program used to use R9 and R10.
Now it fails to compile (out of registers).
I used to know a simpler test but can't remember it.

Learned something new: Rietveld refuses change
list descriptions bigger than 10 kB.

int sum(int x, int y, int z, int w) {
        return
        (((((((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))|
        (((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))))/
        ((((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))|
        (((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))))%
        (((((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))|
        (((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))))/
        ((((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))|
        (((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))))))*
        ((((((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))|
        (((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))))/
        ((((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))|
        (((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))))%
        (((((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))|
        (((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))))/
        ((((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))|
        (((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))))))*
        (((((((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))|
        (((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))))/
        ((((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))|
        (((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))))%
        (((((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))|
        (((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))))/
        ((((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))|
        (((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))))))*
        ((((((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))|
        (((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))))/
        ((((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))|
        (((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))))%
        (((((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))|
        (((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))))/
        ((((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))|
        (((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w))&
        ((x*y+z*w|x*y+z*w)^
        (x*y+z*w|x*y+z*w)))))))
        ;
}

R=ken2
CC=golang-dev
https://golang.org/cl/4650053

2 files changed, 5 insertions, 26 deletions

diff --git a/src/cmd/5c/txt.c b/src/cmd/5c/txt.c
index 4be1f6f620..a32387bc1e 100644
--- a/src/cmd/5c/txt.c
+++ b/src/cmd/5c/txt.c
@@ -292,8 +292,7 @@ tmpreg(void)
 void
 regalloc(Node *n, Node *tn, Node *o)
 {
-	int i, j;
-	static int lasti;
+	int i;
 
 	switch(tn->type->etype) {
 	case TCHAR:
@@ -310,16 +309,9 @@ regalloc(Node *n, Node *tn, Node *o)
 			if(i >= 0 && i < NREG)
 				goto out;
 		}
-		j = lasti + REGRET+1;
-		for(i=REGRET+1; i<NREG; i++) {
-			if(j >= NREG)
-				j = REGRET+1;
-			if(reg[j] == 0) {
-				i = j;
+		for(i=REGRET+1; i<=REGEXT-2; i++)
+			if(reg[i] == 0)
 				goto out;
-			}
-			j++;
-		}
 		diag(tn, "out of fixed registers");
 		goto err;
 
@@ -331,16 +323,9 @@ regalloc(Node *n, Node *tn, Node *o)
 			if(i >= NREG && i < NREG+NFREG)
 				goto out;
 		}
-		j = 0*2 + NREG;
-		for(i=NREG; i<NREG+NFREG; i++) {
-			if(j >= NREG+NFREG)
-				j = NREG;
-			if(reg[j] == 0) {
-				i = j;
+		for(i=NREG; i<NREG+NFREG; i++)
+			if(reg[i] == 0)
 				goto out;
-			}
-			j++;
-		}
 		diag(tn, "out of float registers");
 		goto err;
 	}
@@ -350,9 +335,6 @@ err:
 	return;
 out:
 	reg[i]++;
-/* 	lasti++;	*** StrongARM does register forwarding */
-	if(lasti >= 5)
-		lasti = 0;
 	nodreg(n, tn, i);
 }
 
diff --git a/src/pkg/runtime/Makefile b/src/pkg/runtime/Makefile
index b122e05999..79f847e64a 100644
--- a/src/pkg/runtime/Makefile
+++ b/src/pkg/runtime/Makefile
@@ -12,9 +12,6 @@ SIZE_amd64=64
 SIZE_arm=32
 SIZE=$(SIZE_$(GOARCH))
 
-# TODO(kaib): fix register allocation to honor extern register so we
-# can enable optimizations again.
-CFLAGS_arm=-N
 CFLAGS_windows=-D__WINDOWS__
 CFLAGS=-I$(GOOS) -I$(GOARCH) -I$(GOOS)/$(GOARCH) -wF $(CFLAGS_$(GOARCH)) $(CFLAGS_$(GOOS))